• Computers and Concrete
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• 제23권4호
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• pp.245-253
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• 2019

The studies on the applications of waste materials in concrete have been increased in Iraq since 2003. In this research, rubber wastes that resulting from scrapped tires was added to concrete mix with presence of superplasticizer. The mechanical properties of concrete and workability of concrete mixes were studied. The used rubber were ranging in size from (2-4) mm with addition percentages of (0.1% and 0.2%) by volume of concrete. The results of mechanical properties of concrete show that rubber enhance the ductility, and compressive and tensile strength compared to concrete without it. Also, the flexural behavior of hybrid strength concrete beams (due to using rubber at the bottom or top layer of section) was investigated. The rubber concrete located at bottom layer gives higher values of ultimate loads and deflections compared to the beam with top layer. A similar response to fiber concrete beam (all section contains 0.1% rubber) was recognized. Finite element modeling in three dimensions was carried for the tested beams using ABAQUS software. The ultimate loads and deflection obtained from experimental and finite elements are in good agreements with average difference of 8% in ultimate load and 20% in ultimate deflection.

• Structural Engineering and Mechanics
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• 제83권5호
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• pp.671-680
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• 2022

The shear capacity of beams is an essential parameter in designing beams carrying shear loads. Precise estimation of the ultimate shear capacity typically requires comprehensive calculation methods. For steel fiber reinforced concrete (SFRC) beams, traditional design methods may not accurately predict the interaction between different parameters affecting ultimate shear capacity. In this study, artificial neural network (ANN) modeling was utilized to predict the ultimate shear capacity of SFRC beams using ten input parameters. The results demonstrated that the ANN with 30 neurons had the best performance based on the values of root mean square error (RMSE) and coefficient of determination (R²) compared to other ANN models with different neurons. Analysis of the ANN model has shown that the clear shear span to depth ratio significantly affects the predicted ultimate shear capacity, followed by the reinforcement steel tensile strength and steel fiber tensile strength. Moreover, a Genetic Algorithm (GA) was used to optimize the ANN model's input parameters, resulting in the least cost for the SFRC beams. Results have shown that SFRC beams' cost increased with the clear span to depth ratio. Increasing the clear span to depth ratio has increased the depth, height, steel, and fiber ratio needed to support the SFRC beams against shear failures. This study approach is considered among the earliest in the field of SFRC.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.540-543
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• 2004

In this study, the validity of the grid softened strut-tie model method suggested for concrete member analysis is examined through the ultimate strength evaluation of the reinforced concrete beams. The evaluated results of ultimate strength by the grid softened strut-tie model method were compared with those by the ACI 318-02 and the modified compression field theory, and European codes.

• International Journal of Safety
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• 제11권2호
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• pp.26-28
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• 2012

In this thesis, fracture tests were carried out in order to investigate the flexural strength behavior of FRC(fiber reinforced concrete) structures. FRC beams were used in the tests, the initial crack load and the ultimate load of the beams were observed under the static loading. According to the results, the ultimate loads increase with the fiber content, and these tendency is clear in the specimens with large fiber aspect ratio. From the results of the regression analysis, practical formulae for predicting the flexural strength of FRC were suggested.

• 대한조선학회지
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• 제19권1호
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• pp.33-39
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• 1982

An experimental investigation on the ultimate load and energy absorption of thin plates is presented, which enables the damage to ship involved in a collision to be estimated in terms of the lost kinetic energy. The derived formulae are based upon experimental analysis and compared with theoretical presentations published by some authors. A relationship is found between the absorbed energy and the volume of damaged steel plates.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.230-237
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• 2000

Tubular joints of jacket structures are usually reinforced using thicker can section, internally ring stiffeners, diaphragm, or externally gusset plates to increase load carry capacity. In this paper, the effect of reinforcement type and geometric parameters of stiffener on the ultimate strength of tubular X-joints subjected to brace compression have been studied numerically Three reinforcement methods were considered; (1)can reinforcement (2)internally ring stiffener (3)internally longitudinal diaphragm. The ANSYS software was used nonlinear strength analysis. It was found that there is significant strength enhancement for reinforced joints.

• Steel and Composite Structures
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• 제17권1호
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• pp.83-103
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• 2014

The objective of this research is to study the ultimate moment capacity of the connections between steel I-beams and concrete-filled steel tube columns using different stiffener configurations. The main parameters considered are column cross section shape, square or circular, and filling the column with concrete. This analytical study includes finite element models using ANSYS program taking geometric and material nonlinearities into consideration. These models are verified against the experimental results obtained from previous researches and current design guides. The results show that using proper stiffener configuration affects the stress distribution through the connection and increases the ultimate moment capacity of the connections. Also, circular column is advantageous than the square column for all stiffener configurations and dimensions.

• Computers and Concrete
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• 제26권4호
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• pp.351-365
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• 2020

This work presents numerical and experimental analyses of the behavior of reinforced-concrete deep beams with unconventional geometries. The main goal here is to experimentally and numerically study these geometries to find possible new behaviors due to the material nonlinearity of reinforced concrete with complex geometries. Usually, unconventional geometries result from innovative designs; in general, studies of reinforced concrete structures are performed only on conventional members such as beams, columns, and labs. To achieve the goal, four reinforced-concrete deep beams with geometries not addressed in the literature were tested. The models were numerically analyzed with the Adaptive Micro Truss Model (AMTM), which is the proposed method, to address new geometries. This work also studied the main parameters of the constitutive model of concrete based on a statistical analysis of the finite element (FE) results. To estimate the ultimate loads, FE simulations were performed using the Monte Carlo method. Based on the obtained ultimate loads, a probabilistic distribution was created, and the final ultimate loads were computed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.609-612
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• 1999

This study presents the plastic analysis for the flexural and shear strength of RC beams related to anchorage failure. Five failure mechanisms based on the upper bound solution were constructed and the ultimate strength equations were formulated from them. The parametric study herein was carried out to observe the variation of the controlling failure mechanism depending on the parameters in the ultimate strength equations. The results of the parametric study show that controlling failure mechanism and ultimate strength are determined through the interaction of each parameter. This indicated that respective structural configuratins must be treated in a unified manner. Additionally this study proposes the scope of the parameter to induce the flexural of RC deep beams.

• 한국강구조학회 논문집
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• 제11권2호통권39호
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• pp.233-240
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• 1999

콘크리트충전 강관 단주의 최대내력은 강관에 의한 내부 콘크리트의 구속효과로 단순누가에 의한 내력보다도 높게 나타난다는 것은 이미 여러 연구자들에 의해 알려져 있다. 본 연구는 강관의 지름-두께비와 콘크리트 강도 그리고 등가 세장비의 변화에 따른 내력 예측식을 여러 연구자들의 실험결과를 이용하여 비교 분석하고 회귀식을 구한다.